[vlc-devel] [3.0] backport tools/contribs/build.sh

[Steve Lhomme]

I recently tried to build VLC 3.0 with LLVM to produce PDB files and be 
debugged faster on Windows (gdb sucks on Windows with multiple DLLs).

I backported a lot of files from 4.0 to get to this point adding the 
following features:
- build a patched libtool when compiling with Clang
- build a CMake with Hugo's patch for pkgconfig
- build a locally fixed Meson
- enable PDB support in VLC
- update contribs to use pthreadGC2 properly
- update Qt to a version that builds with clang-win32 (Qt 5.12.7 is LTS)
- clean _WIN32_WINNT forcing as we use a more recent mingw64
- build out of tree (which has patches intertwined with other changes)

The result of all this is in this branch:
https://code.videolan.org/robUx4/vlc/-/tree/3.0/llvm

It's mostly back porting with a few edited files. I'd like to get this 
merged but there are almost 150 individual patches. Most of them have 
been reviewed on master already and are in use today. Some I had to edit 
and are marked as such.

I'm not sure how to get this done properly.